Research On Regulation Of Electrocatalvtic Hydrogen Evolution Of TMDs By Defects

At present,it is urgent to find catalysts with excellent catalytic activity and high chemical stability to realize the application of hydrogen energy.Transition metal dichalcogenides(TMDs)are potential candidates for hydrogen evolution reaction electrocatalysts due to their unique structures and superior electronic properties.This study explores the structural properties,electrocatalytic hydrogen evolution activity and electronic properties of transition metal dichalcogenides MX2(M=Pt,Pd;X=S,Se,Te)through first-principles,and further improve the catalytic activity through the introduction of single-atom defects and vacancies,providing a theoretical basis for the application of TMDs catalysts for hydrogen evolution reaction.(1)Based on density functional theory,we explored the structural stability and electrocatalytic hydrogen evolution reaction properties of intrinsic structures of 1T phase TMDs and single-atom doping(B,C,N,P,Au,Ag,Cu,Co,Fe,Ni,Zn),and the mechanism of defects affecting the efficiency of electrocatalytic hydrogen evolution reaction was analyzed.Calculated defect formation energies indicate that most defect structures are thermodynamically stable.Single-atom doping and vacancies significantly enhance the hydrogen evolution catalytic performance of the basal plane.In particular,the Gibbs Free energy values of Zn-doped and Te-vacancy PtTe2 are close to zero,exhibiting excellent catalytic activity.Furthermore,the reasons for the enhanced hydrogen evolution performance are further revealed through the electronic structure and charge transfer analysis.(2)The structural properties,electrocatalytic activity and vacancy defect regulation mechanism of novel pentagonal PdS2 and PdSe2 were investigated.The inert basal planes of PdS2 and PdSe2 are activated by constructing three vacancies(VS/Se,VPd,DVS/Se)on the surface.The results show that VS/Se and VPd vacancies significantly enhance the electrocatalytic performance of pentagonal TMDs,and it can be further tuned by the vacancy concentration.Especially 2.78%Vs PdS2,50%VPd PdS2 and 12.5%VSe PdSe2 show the best electrocatalytic activity.Further analysis of charge transfer and band structure reveal the effect of vacancies on electronic properties and reasons for the improved catalytic activity.